Do not stop taking sildenafil without talking to your doctor. What side effects can this medication cause? Ask your healthcare professional how you should dispose of any medicine you do not use. Angina severe chest pain , unstable or Arrhythmia irregular heartbeat, within the last 6 months or Blood vessel problems eg, aortic stenosis, idiopathic subaortic stenosis or Heart attack within the last 6 months or Heart failure or Hypertension high blood pressure or Hypotension low blood pressure or Retinal disorders eye problem or Retinitis pigmentosa an inherited eye disorder or Stroke within the last 6 months —Should not be used in patients with these conditions. Its effects might last longer if you have mild to moderate ED. Children 1 year of age and older weighing 20 kg or less—10 mg 3 times a day.Viagra (sildenafil) is a prescription drug that’s used to treat erectile dysfunction (ED). The drug comes as a tablet you’ll take by swallowing. It’s usually taken as needed about 1 . Viagra is a brand-name prescription drug that’s approved to treat erectile dysfunction (ED). With ED, you’re unable to have or maintain an erection. Viagra is approved for this use . Viagra is classified as a phosphodiesterase type 5 (PDE5) inhibitor. For information on the dosage of Viagra, including its pill form, strengths, and how to take the drug, keep .